Has there been any progress on this issue? I’m having the same problem.
I flattened a path with the blur effect, flattened all imported bitmap images, deleted all text layers (after converting to paths), none of this helped.
I found a work-around but I’d like to get to the source of the problem.
I’m on MacOS. I open the PDF with Preview.app, export it as a PDF, then Acrobat opens it just fine.